The object of the research is to study behavioral implications of beta-alanine metabolism in Drosophila melanogaster under natural and artificial conditions. Laboratory mutant flies, as well as flies extracted from nature, which show polymorphism in levels of beta-alanine accumulation in the body fluids, will be studied. Beta-alanine accumulation will be determined by injection of C-14-labeled beta-alanine. In behavioral studies of flies in a light gradient, special attention is paid to sexual isolation, habitat selection, and differential aggression, of the polymorphic forms and their heterozygotes. Attempts will then be made to simulate the findings in flies artifically injected with beta-alanine as pupae and adults to produce behavioral phenocopies. Population studies of flies found in the original populations in nature, and similar populations kept in cages, will supplement findings of differential behavior.